turn 'OpenGraph' into a more general purpose HTTP meta facility for setting any meta header

Zotlabs/Web/HttpMeta.php

@@ -0,0 +1,66 @@
+<?php
+
+namespace Zotlabs\Web;
+
+
+class HttpMeta {
+
+	private $vars = null;
+	private $og = null;
+
+	function __construct() {
+
+		$this->vars = array();
+		$this->og = array();
+
+	}
+
+	function set($property,$value) {
+		if(strpos($property,'og:') === 0)
+			$this->og[$property] = $value;
+		else
+			$this->vars[$property] = $value;
+	}
+
+	function check_required() {
+		if(
+			($this->og) 
+			&& array_key_exists('og:title',$this->og) 
+			&& array_key_exists('og:type', $this->og) 
+			&& array_key_exists('og:image',$this->og) 
+			&& array_key_exists('og:url',  $this->og)
+		)
+			return true;
+		return false;
+	}
+
+	function get_field($field) {
+		if(strpos($field,'og:') === 0)
+			$arr = $this->og;
+		else
+			$arr = $this->vars;
+
+		if($arr && array_key_exists($field,$arr) && $arr[$field])
+			return $arr[$field];
+		return false;
+	}
+
+
+	function get() {
+		$o = '';
+		if($this->vars) {
+			foreach($this->vars as $k => $v) {
+				$o .= '<meta property="' . $k . '" content="' . urlencode($v) . '" />' . "\r\n" ;
+			}
+		}
+		if($this->check_required()) {
+			foreach($this->og as $k => $v) {
+				$o .= '<meta property="' . $k . '" content="' . urlencode($v) . '" />' . "\r\n" ;
+			}
+		}
+		if($o)
+			return "\r\n" . $o;
+		return $o;
+	}
+
+}